, HALOALKANES AND HALOARENES
2016
1) Write the structure of an isomer of compound C4H9Br which is most
reactive towards SN1 reaction.
Ans. tert butyl bromide
2) How do you convert:
i) Chlorobenzene to biphenyl
in) Propene to 1-iodopropane
iii) 2-bromobutane to but-2-ene
Ans. i)
ii)
iii)
3) Write the major Product(s) in the following:
I.
, II.
III.
Ans. i. ii. iii.
2017
1) The following compounds are given to you :
2-Bromopentane, 2-Bromo-2-methylbutane, 1-Bromopentane
(a) Write the compound which is most reactive towards SN2 reaction.
(b) Write the compound which is optically active.
(c) Write the compound which is most reactive towards β-elimination
reaction
Ans. (a) 1- Bromopentane is most reactive towards SN2 reaction.
(b) 2-Bromo-2-methylbutane
(c) 2- Bromopentane is most reactive towards β-elimination reaction with
product of pent-1-ene pent-2-ene.
2018
1) Out of chlorobenzene and benzyl chloride, which one gets easily
hydrolysed by aqueous NaOH and why?
Ans. Benzyl chloride
2) a) Identify the chiral molecule in the following pair:
b) Write the structure of the product when chlorobenzene is treated
with methyl chloride in the presence of sodium metal and dry ether
c) Write the structure of the alkene formed by dehydrohalogenation of
1-bromo-1 methylcyclohexane with alcoholic KOH.
Ans. (A) (i)
, 2019
1) Out of Chlorobenzene and Cyclohexyl chloride, which one is more
reactive towards nucleophilic substitution reaction and why?
Ans. Cyclohexyl chloride
2) Among all the isomers of molecular formula C4HBr, identify
(a) the one isomer which is optically active.
(b) the one isomer which is highly reactive towards SN2.
(c) the two isomers which give same product on dehydrohalogenation
with alcoholic KOH.
Ans. a)
b)
3) Why is chloroform kept in dark coloured bottles ?
Ans. to avoid the formation of phosgene
4)
(a) Out of and , which one is more reactive
towards SN2 reaction and why ?
(b) Out of and which one is more reactive
towards nucleophilic substitution reaction and why ?
2016
1) Write the structure of an isomer of compound C4H9Br which is most
reactive towards SN1 reaction.
Ans. tert butyl bromide
2) How do you convert:
i) Chlorobenzene to biphenyl
in) Propene to 1-iodopropane
iii) 2-bromobutane to but-2-ene
Ans. i)
ii)
iii)
3) Write the major Product(s) in the following:
I.
, II.
III.
Ans. i. ii. iii.
2017
1) The following compounds are given to you :
2-Bromopentane, 2-Bromo-2-methylbutane, 1-Bromopentane
(a) Write the compound which is most reactive towards SN2 reaction.
(b) Write the compound which is optically active.
(c) Write the compound which is most reactive towards β-elimination
reaction
Ans. (a) 1- Bromopentane is most reactive towards SN2 reaction.
(b) 2-Bromo-2-methylbutane
(c) 2- Bromopentane is most reactive towards β-elimination reaction with
product of pent-1-ene pent-2-ene.
2018
1) Out of chlorobenzene and benzyl chloride, which one gets easily
hydrolysed by aqueous NaOH and why?
Ans. Benzyl chloride
2) a) Identify the chiral molecule in the following pair:
b) Write the structure of the product when chlorobenzene is treated
with methyl chloride in the presence of sodium metal and dry ether
c) Write the structure of the alkene formed by dehydrohalogenation of
1-bromo-1 methylcyclohexane with alcoholic KOH.
Ans. (A) (i)
, 2019
1) Out of Chlorobenzene and Cyclohexyl chloride, which one is more
reactive towards nucleophilic substitution reaction and why?
Ans. Cyclohexyl chloride
2) Among all the isomers of molecular formula C4HBr, identify
(a) the one isomer which is optically active.
(b) the one isomer which is highly reactive towards SN2.
(c) the two isomers which give same product on dehydrohalogenation
with alcoholic KOH.
Ans. a)
b)
3) Why is chloroform kept in dark coloured bottles ?
Ans. to avoid the formation of phosgene
4)
(a) Out of and , which one is more reactive
towards SN2 reaction and why ?
(b) Out of and which one is more reactive
towards nucleophilic substitution reaction and why ?
